Julemøde torsdag den 2. december kl. 19.00

Til årets juleforedrag afprøver vi ny teknik med et foredrag transmitteret direkte fra Nortwestern University, IL, USA. Julemødet holdes torsdag den 2. december kl. 19.00 på DTU, bygning 204 stuen, kollokvierummet. Foredragene vil være om AC impedans målinger til undersøgelse af tynd film og bulk keramisk materialer samt et om undersøgelse af korrosion af stål i beton. Der vil her være en mulighed for at opleve hvordan, det på det seneste meget omtalte, ”E-learning” eller ”det virtuelle klasseværelse” virker i praktisk.

Efter foredraget vil der traditionen tro blive serveret en ikke virtuel gløgg og æbleskiver.

E-learning – konsortiet på DTU vil I anledning af Julemødet i Dansk Elektrokemisk Forening uden omkostninger for DEF forestå transmission af to miniforelæsninger fra, Northwestern University, Evanston, IL, USA. Til Danmark henholdsvis Lyngby samt evt. andre steder. Den samledes varighed af de to miniforelæsninger vil være ca. 60 minutter – hvert efterfulgt af en verbal dialog fra deltagerne på DTU og samt evt. andre steder. Forelæsningerne foregår således symmetrisk, men med en tidsforskel på 7 timer mellem Danmark og USA. Forelæsning vil finde sted i Bygning 204 (stuen) kollokvierummet.

Per Møller

På vegne af E-learning – consortium.org på DTU

An introduction to: AC Impedance Spectroscopy to Electrically Characterize Ceramic Bulk and Thin Film Materials.

Thomas O. Mason

BS, Ceramic Science, Pennsylvania State University, University Park, PA, USA

PhD, Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA

Charles Deering McCormick Professor of Teaching Excellence, Northwestern University, Evanston, IL, USA

AC-Impedance Spectroscopy (AC-IS) can be employed in the study of composites.  In matrices which are ionic conductors, at least two arcs are observed.  The low frequency arc is associated with electrode processes and is the realm of Electrochemical Impedance Spectroscopy (EIS).  The high frequency arc provides important information regarding bulk phenomena—ionic transport and dielectric response.  When highly conductive second phases like particles or fibers are added, this arc becomes further subdivided into two arcs.  We have demonstrated that much information can be obtained by thorough analysis of the two “cusps” (electrode-bulk 1 and bulk 1-bulk 2).  In this talk, we consider several examples:  1) particulate cement-based composites, 2) fiber-reinforced cement-based composites (FRCs), and 3) a procedure for determining the conductivity of ceramic particles of moderate conductivity (via a “powder-solution-composite” or PSC approach).  In the case of FRCs, considerable information is available regarding fiber alignment, segregation and/or clumping.  Using the PSC apparatus, conductivities of novel p-type transparent conducting oxides have been successfully measured.

Corrosion of Steel in Concrete - AC Impedance Spectroscopy for Quantification of the Effect of Rebar Surface Treatments.

Andre Küter

Pre-degree, Civil Engineering, RWTH Aachen University of Technology, Aachen, Germany

MSc, Structural Engineering, Chalmers University of Technology, Gothenburg, Sweden

PhD Candidate, Management of Reinforcement Corrosion, DTU-Byg and IPL, Lyngby, Denmark

Throughout the world concrete is the most widely used construction material in buildings and civil engineering structures. Most concrete structures have performed satisfactory over many decades, but there are still an unacceptable large number of concrete structures that deteriorate prematurely. It has been estimated that at least 50% of Europe’s annual construction budget is currently spent on rehabilitation of existing structures. This figure will increase as structures from the infrastructure boom of the 1970’s start to require repair and refurbishment. Measures to reduce the costs of maintenance and repair of concrete structures are therefore in growing demand.

Reinforcement corrosion is the most important deterioration mechanism, with regard to costs and consequences. Steel is normally protected in concrete due its high alkalinity; corrosion is e.g. initiated by chloride ions.

In the above mini lecture André Küter from DTU will inform about his research work in the group of Professor Mason, where AC Impedance Spectroscopy is used for the Quantification of the corrosion of rebars.